Pregnancy and phaeochromocytoma/paraganglioma: clinical clues affecting diagnosis and outcome - a systematic review.

BACKGROUND: Phaeochromocytoma and paraganglioma (PPGL) in pregnancy, if not diagnosed antepartum, pose a high risk for mother and child. OBJECTIVE: To examine the clinical clues of antepartum and postpartum/postmortem diagnosis of PPGL. SEARCH STRATEGY: Case reports on PPGL in pregnancy published between 1 January 1988 and 30 June 2019 in English, German, Dutch or French. SELECTION CRITERIA: Case reports containing a predefined minimum of clinical data on PPGL and pregnancy. DATA COLLECTION AND ANALYSIS: Two authors independently performed data extraction and assessed data quality. We calculated odds ratios (OR) (with 95% confidence intervals) and used uni- and multivariable logistic regression analysis. MAIN RESULTS: Maternal and fetal/neonatal mortalities were 9.0% (18/200) and 14.2% (29/204), respectively. Maternal mortality was 42-fold higher with PPGL diagnosed postpartum/postmortem (17/58; 29.3%) than antepartum (1/142; 0.7%) (adjusted OR 45.9, 95% CI 5.67-370, P = 0.0003). Offspring mortality was 2.6-fold higher with PPGL diagnosed postpartum/postmortem than antepartum (OR 3.1, 95% CI 1.38-6.91, P = 0.0044). Hypertension at admission (OR 2.29, 95% CI 1.12-4.68, P = 0.022), sweating (OR 3.14, 95% CI 1.29-7.63, P = 0.014) and a history of PPGL, a known PPGL-associated gene mutation or adrenal mass (OR 8.87, 95% CI 1.89-41.64, P = 0.0056) were independent factors of antepartum diagnosis. Acute onset of symptoms (OR 8.49, 95% CI 3.52-20.5, P < 0.0001), initial diagnosis of pre-eclampsia (OR 6.34, 95% CI 2.60-15.5, P < 0.0001), admission for obstetric care (OR 10.71, 95% CI 2.70-42.45, P = 0.0007) and maternal tachycardia (OR 2.72, 95% CI 1.26-5.85, P = 0.011) were independent factors of postpartum diagnosis. CONCLUSION: Several clinical clues can assist clinicians in considering an antenatal diagnosis of PPGL in pregnancy, thus potentially improving outcome. TWEETABLE ABSTRACT: Systematic review of 204 pregnant patients with phaeochromocytoma identified clinical clues for a timely antepartum diagnosis.

Steroid Hormone Production in Patients with Aldosterone Producing Adenomas.

Primary aldosteronism encompasses 2 major underlying causes: (1) aldosterone producing adenoma and (2) bilateral adrenal hyperplasia. In addition to the aldosterone excess, increased production of other compounds of the steroidogenic pathways may be involved. Until recently, most studies examined the production of steroids other than aldosterone in tumor tissue, urine, or peripheral plasma samples, but several new studies have also addressed steroid levels in adrenal venous blood samples using liquid chromatography tandem mass spectrometry. Plasma and tissue levels of several precursors of aldosterone with mineralocorticoid activity are higher in patients with aldosterone producing adenomas than in those with bilateral hyperplasia. These include corticosterone, deoxycorticosterone, and their 18-hydroxylated metabolites. Similarly, urinary, peripheral, and adrenal venous concentrations of the hybrid steroids 18-oxocortisol and 18-hydroxycortisol are higher in patients with aldosterone producing adenomas than in bilateral hyperplasia. Differences in the pathophysiology and in clinical and biochemical phenotypes caused by aldosterone producing adenomas and bilateral adrenal hyperplasia may be related to the differential expression of steroidogenic enzymes, and associated to specific underlying somatic mutations. Correct appreciation of differences in steroid profiling between aldosterone producing adenomas and bilateral adrenal hyperplasia may not only contribute to a better understanding of the pathogenesis of primary aldosteronism but may also be helpful for future subtyping of primary aldosteronism.

Valproic acid enhances neuronal differentiation of sympathoadrenal progenitor cells.

The antiepileptic drug valproic acid (VPA) has been shown to influence the neural differentiation and neurite outgrowth of neural stem cells. Sympathoadrenal progenitor cells share properties with neural stem cells and are considered a potential cell source in the treatment of neurodegenerative diseases. The present study therefore aims at modulating the neural differentiation potential of these cells by treatment with the histone deacetylase inhibitor VPA. We studied the epigenetic effects of VPA in two culture conditions: suspension conditions aimed to expand adrenomedullary sympathoadrenal progenitors within free-floating chromospheres and adherent cell cultures optimized to derive neurons. Treatment of chromospheres with VPA may launch neuronal differentiation mechanisms and improve their neurogenic potential upon transplantation. However, also transplantation of differentiated functional neurons could be beneficial. Treating chromospheres for 7 days with clinically relevant concentrations of VPA (2 mm) revealed a decrease of neural progenitor markers Nestin, Notch2 and Sox10. Furthermore, VPA initiated catecholaminergic neuronal differentiation indicated by upregulation of the neuronal marker ß-III-tubulin, the dopaminergic transcription factor Pitx3 and the catecholaminergic enzymes TH and GTPCH. In adherent neural differentiation conditions, VPA treatment improved the differentiation of sympathoadrenal progenitor cells into catecholaminergic neurons with significantly elevated levels of nor- and epinephrine. In conclusion, similar to neural stem cells, VPA launches differentiation mechanisms in sympathoadrenal progenitor cells that result in increased generation of functional neurons. Thus, data from this study will be relevant to the potential use of chromaffin progenitors in transplantation therapies of neurodegenerative diseases.

Genotype-specific differences in the tumor metabolite profile of pheochromocytoma and paraganglioma using untargeted and targeted metabolomics.

CONTEXT AND OBJECTIVE: Pheochromocytomas and paragangliomas (PGLs) are neuroendocrine tumors of sympathetic or parasympathetic paraganglia. Nearly 40% of PGLs are caused by germline mutations. The present study investigated the effect of genetic alterations on metabolic networks in PGLs. DESIGN: Homogenates of 32 sporadic PGLs and 48 PGLs from patients with mutations in SDHB, SDHD, SDHAF-2, VHL, RET, and NF-1 were subjected to proton ((1)H) nuclear magnetic resonance (NMR) spectroscopy at 500 MHz for untargeted and HPLC tandem mass spectrometry for targeted metabolite profiling. RESULTS: (1)H NMR spectroscopy identified 28 metabolites in PGLs of which 12 showed genotype-specific differences. Part of these results published earlier reported low complex II activity (P < .0001) and low ATP/ADP/AMP content (P < .001) in SDH-related PGLs compared with sporadics and PGLs of other genotypes. Extending these results, low levels of N-acetylaspartic acid (NAA; P < .05) in SDH tumors and creatine (P < .05) in VHL tumors were observed compared with sporadics and other genotypes. Positive correlation was observed between NAA and ATP/ADP/AMP content (P < .001) and NAA and complex II activity (P < .0001) of PGLs. Targeted purine analysis in PGLs showed low adenine in cluster 1 compared with cluster 2 tumors (SDH P < .0001; VHL P < .05) whereas lower levels (P < .05) of guanosine and hypoxanthine were observed in RET tumors compared with SDH tumors. Principal component analysis (PCA) of metabolites could distinguish PGLs of different genotypes. CONCLUSIONS: The present study gives a comprehensive picture of alterations in energy metabolism in SDH- and VHL-related PGLs and establishes the interrelationship of energy metabolism and amino acid and purine metabolism in PGLs.

Changes in morphology and function of adrenal cortex in mice fed a high-fat diet.

BACKGROUND/OBJECTIVES: Obesity is a major risk factor for the development of type 2 diabetes and other debilitating diseases. Obesity and diabetes are intimately linked with altered levels of adrenal steroids. Elevated levels of these hormones induce insulin resistance and cause cardiovascular diseases. The mechanisms underlying obesity-related alterations in adrenal steroids are still not well understood. Here, we investigated how diet-induced obesity affects the morphology and function of the mouse adrenal cortex. METHODS: We fed animals either a high-fat diet (HFD) or a normal diet (60% kcal from fat or 10% kcal from fat, respectively) for 18 weeks. We then assessed various aspects of adrenal gland morphology and function, as well as basal plasma concentrations of steroid hormones and ACTH. RESULTS: We show that adrenal glands of mice fed a HFD release more corticosterone and aldosterone, resulting in higher plasma levels. This increase is driven by adrenal cortical hyperplasia, and by increased expression of multiple genes involved in steroidogenesis. We demonstrate that diet-induced obesity elevates Sonic hedgehog signaling in Gli1-positive progenitors, which populate the adrenal capsule and give rise to the steroidogenic cells of the adrenal cortex. Feeding animals with a HFD depletes Gli1-positive progenitors, as the adrenal cortex expands. CONCLUSIONS: This work provides insight into how diet-induced obesity changes the biology of the adrenal gland. The association of these changes with increased Shh signaling suggests possible therapeutic strategies for obesity-related steroid hormone dysfunction.

Genetics and the clinical approach to paragangliomas.

This study analyses new information on gene mutations in paragangliomas and puts them into a clinical context. A suspicion of malignancy is critical to determine the workup and surgical approach in adrenal (A-PGL) and extra-adrenal (E-PGL) paragangliomas (PGLs). Malignancy rates vary with location, family history, and gene tests results. Currently there is no algorithm incorporating the above information for clinical use. A sum of 1,821 articles were retrieved from PubMed using the search terms "paraganglioma genetics". Thirty-seven articles were selected of which 9 were analyzed. It was found that 599/2,487 (24%) patients affected with paragangliomas had a germline mutation. Of these 30.2% were mutations in SDHB, 25% VHL, 19.4% RET, 18.4% SDHD, 5.0% NF1, and 2.0% SDHC genes. A family history was positive in 18.1-64.3% of patients. Adrenal PGLs accounted for 55.1% in mutation (+) and 81.0% in mutation (-) patients (RR 1.2, p < 0.0001). Bilateral A-PGLs accounted for 56.4% in mutation (+) and 3.2% in mutation (-) patients (RR 8.7, p < 0.0001). E-PGL were found in 33.6% of mut+ and 17.3% of mut- (RR 1.7, p < 0.0001). In mutation (+) patients PGLs malignancy varied with location, adrenal (6.4%) thoraco-abdominal E-PGL (38%), H & N E-PGL (10%). Malignancy rates were 8.2% in mutation (-) and lower in mutation (+) PGLs except for SDHB 36.5% and SDHC 8.3%. Exclusion of a mutation lowered the probability of malignancy significantly in E-PGL (RR 0.03 (95% CI 0.1-0.6); p < 0.001). Mutation analysis provides valuable preoperative information to assess the risk of malignancy in A-PG and E-PGLs and should be considered in the work up of all E-PGL lesions.

[Pheochromocytoma: update on diagnosis and therapy]. / Phäochromozytom: Diagnostik und Therapie.

Pheochromocytomas (P) are rare catecholamine producing neuroendocrine tumors originating from the chromaffin cells of the adrenal medulla or in 15 % of cases from extra adrenal chromaffin tissue and termed paragangliomas (PGL). Because of secretion of the catecholamines - adrenaline, noradrenaline and dopamine - the tumors are dangerous with a risk of life threating hypertensive crises. Measurements of plasma metanephrine, normetanephrine and methoxytyramine by liquid chromatography with tandem mass spectrometry provides the most accurate and precise method for biochemical diagnosis. Approximately 30-40 % of the tumors have a hereditary background due to mutations of 11 known susceptibility genes, with identification facilitated by targeted genetic testing according to clinical presentation. Apart from syndrome-dependent clinical stigmata, other hints to an underlying mutation can be provided by biochemical profiles of the catecholamine metabolites, tumor location, patient age and presence of metastatic disease. Surgery with minimal invasive procedures is the recommended therapeutic way after pretreatment with an alpha receptor blocking medication.

Mortality associated with phaeochromocytoma.

Two major categories of mortality are distinguished in patients with phaeochromocytoma. First, the effects of excessive circulating catecholamines may result in lethal complications if the disease is not diagnosed and/or treated timely. The second category of mortality is related to development of metastatic disease or other neoplasms. Improvements in disease recognition and diagnosis over the past few decades have reduced mortality from undiagnosed tumours. Nevertheless, many tumours remain unrecognised until they cause severe complications. Death resulting from unrecognised or untreated tumour is caused by cardiovascular complications. There are also numerous drugs and diagnostic or therapeutic manipulations that can cause fatal complications in patients with phaeochromocytoma. Previously it has been reported that operative mortality was as high as 50% in unprepared patients with phaeochromocytoma who were operated and in whom the diagnosis was unsuspected. Today mortality during surgery in medically prepared patients with the tumour is minimal. Phaeochromocytomas may be malignant at presentation or metastases may develop later, but both scenarios are associated with a potentially lethal outcome. Patients with phaeochromocytoma run an increased risk to develop other tumours, resulting in an increased mortality risk compared to the general population. Phaeochromocytoma during pregnancy represents a condition with potentially high maternal and foetal mortality. However, today phaeochromocytoma in pregnancy is recognised earlier and in conjunction with improved medical management, maternal mortality has decreased to less than 5%.

[Diagnosis of pheochromocytoma and paraganglioma: the clonidine suppression test in patients with borderline elevations of plasma free normetanephrine]. / Die Diagnose des Phäochromozytoms und Paraganglioms.

BACKGROUND: Measurements of plasma free metanephrines provide a sensitive test for the diagnosis of pheochromocytoma/paraganglioma (P/PGL), with highly elevated levels diagnostic of the disease. However, there is less diagnostic certainty in patients with mild elevations of these catecholamine metabolites. PATIENTS AND METHODS: Here we report use of the clonidine suppression test (CST) as a second-tier diagnostic test in 24 patients with mild elevations of plasma free metanephrines and/or catecholamines. Blood samples before and 3 hours after clonidine were analyzed for plasma concentrations of metanephrines and catecholamines with a negative test result defined as either a clonidine-induced fall in normetanephrine or noradrenaline by more than 40 % and 50 % respectively or to below the upper cut-offs of reference intervals. RESULTS: P/PGLs were confirmed in 9 patients and excluded in 15 by independent criteria. More than half of the patients without P/PGL showed normalized plasma concentrations of normetanephrine at baseline before clonidine compared to initial screening; all showed appropriate clonidine-induced falls in normetanephrine and noradrenaline or levels after the drug below upper cut-offs, indicating a diagnostic specificity of 100 % (CI 78-100 %). However, similar responses for noradrenaline were noted in 7 patients with P/PGL, indicating a diagnostic sensitivity of only 22 % (CI 2,8-60 %) compared to 100 % (CI 66-100 %) for normetanephrine. CONCLUSION: These results support use of the CST in combination with measurements of normetanephrine for confirming or excluding P/PGL in patients with borderline elevated test results, which should, however, first be confirmed by sampling blood under standardized resting conditions.

Anti-tumor effects of peptide analogs targeting neuropeptide hormone receptors on mouse pheochromocytoma cells.

Pheochromocytoma is a rare but potentially lethal chromaffin cell tumor with currently no effective treatment. Peptide hormone receptors are frequently overexpressed on endocrine tumor cells and can be specifically targeted by various anti-tumor peptide analogs. The present study carried out on mouse pheochromocytoma cells (MPCs) and a more aggressive mouse tumor tissue-derived (MTT) cell line revealed that these cells are characterized by pronounced expression of the somatostatin receptor 2 (sst2), growth hormone-releasing hormone (GHRH) receptor and the luteinizing hormone-releasing hormone (LHRH) receptor. We further demonstrated significant anti-tumor effects mediated by cytotoxic somatostatin analogs, AN-162 and AN-238, by LHRH antagonist, Cetrorelix, by the cytotoxic LHRH analog, AN-152, and by recently developed GHRH antagonist, MIA-602, on MPC and for AN-152 and MIA-602 on MTT cells. Studies of novel anti-tumor compounds on these mouse cell lines serve as an important basis for mouse models of metastatic pheochromocytoma, which we are currently establishing.

Genetic screening for von Hippel-Lindau gene mutations in non-syndromic pheochromocytoma: low prevalence and false-positives or misdiagnosis indicate a need for caution.

Genetic testing of tumor susceptibility genes is now recommended in most patients with pheochromocytoma or paraganglioma (PPGL), even in the absence of a syndromic presentation. Once a mutation is diagnosed there is rarely follow-up validation to assess the possibility of misdiagnosis. This study prospectively examined the prevalence of von Hippel-Lindau (VHL) gene mutations among 182 patients with non-syndromic PPGLs. Follow-up in positive cases included comparisons of biochemical and tumor gene expression data in 64 established VHL patients, with confirmatory genetic testing in cases with an atypical presentation. VHL mutations were detected by certified laboratory testing in 3 of the 182 patients with non-syndromic PPGLs. Two of the 3 had an unusual presentation of diffuse peritoneal metastases and substantial increases in plasma metanephrine, the metabolite of epinephrine. Tumor gene expression profiles in these 2 patients also differed markedly from those associated with established VHL syndrome. One patient was diagnosed with a partial deletion by Southern blot analysis and the other with a splice site mutation. Quantitative polymerase chain reaction, multiplex ligation-dependent probe amplification, and comparative genomic hybridization failed to confirm the partial deletion indicated by certified laboratory testing. Analysis of tumor DNA in the other patient with a splice site alteration indicated no loss of heterozygosity or second hit point mutation. In conclusion, VHL germline mutations represent a minor cause of non-syndromic PPGLs and misdiagnoses can occur. Caution should therefore be exercised in interpreting positive genetic test results as the cause of disease in patients with non-syndromic PPGLs.

Adrenomedullary function in patients with nonclassic congenital adrenal hyperplasia.

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is classified into three types based on disease severity: classic salt-wasting, classic simple virilizing, and nonclassic. Adrenomedullary dysplasia and epinephrine deficiency have been described in classic CAH, resulting in glucose dysregulation. Our objective was to investigate adrenomedullary function in nonclassic CAH and to evaluate adrenomedullary function according to disease severity. Adrenomedullary function was evaluated in response to a standardized cycle ergonometer test in 23 CAH patients (14 females, age 9-38 years; 6 salt-wasting, 7 simple virilizing, 5 nonclassic receiving glucocorticoid treatment, 5 nonclassic not receiving glucocorticoid), and 14 controls (7 females, age 12-38 years). Epinephrine, glucose, and cortisol were measured at baseline and peak exercise. CAH patients and controls were similar in age and anthropometric measures. Patients with nonclassic CAH who were not receiving glucocorticoid and controls experienced the expected stress-induced rise in epinephrine, glucose, and cortisol. Compared to controls, patients with all types of CAH receiving glucocorticoid had impaired exercise-induced changes in epinephrine (salt-wasting: p=0.01;simple virilizing: p=0.01; nonclassic: p=0.03), and cortisol (salt-wasting: p=0.004; simple virilizing: p=0.006; nonclassic: p=0.03). Salt-wasting patients displayed the most significant impairment, including impairment in glucose response relative to controls (p=0.03). Hydrocortisone dose was negatively correlated with epinephrine response (r=-0.58; p=0.007) and glucose response (r=-0.60; p=0.002). The present study demonstrates that untreated patients with nonclassic CAH have normal adrenomedullary function. The degree of epinephrine deficiency in patients with CAH is associated with the severity of adrenocortical dysfunction, as well as glucocorticoid therapy.

Expression of neuropeptide hormone receptors in human adrenal tumors and cell lines: antiproliferative effects of peptide analogues.

Peptide analogues targeting various neuropeptide receptors have been used effectively in cancer therapy. A hallmark of adrenocortical tumor formation is the aberrant expression of peptide receptors relating to uncontrolled cell proliferation and hormone overproduction. Our microarray results have also demonstrated a differential expression of neuropeptide hormone receptors in tumor subtypes of human pheochromocytoma. In light of these findings, we performed a comprehensive analysis of relevant receptors in both human adrenomedullary and adrenocortical tumors and tested the antiproliferative effects of peptide analogues targeting these receptors. Specifically, we examined the receptor expression of somatostatin-type-2 receptor, growth hormone-releasing hormone (GHRH) receptor or GHRH receptor splice variant-1 (SV-1) and luteinizing hormone-releasing hormone (LHRH) receptor at the mRNA and protein levels in normal human adrenal tissues, adrenocortical and adrenomedullary tumors, and cell lines. Cytotoxic derivatives of somatostatin AN-238 and, to a lesser extent, AN-162, reduced cell numbers of uninduced and NGF-induced adrenomedullary pheochromocytoma cells and adrenocortical cancer cells. Both the splice variant of GHRH receptor SV-1 and the LHRH receptor were also expressed in adrenocortical cancer cell lines but not in the pheochromocytoma cell line. The GHRH receptor antagonist MZ-4-71 and LHRH antagonist Cetrorelix both significantly reduced cell growth in the adrenocortical cancer cell line. In conclusion, the expression of receptors for somatostatin, GHRH, and LHRH in the normal human adrenal and in adrenal tumors, combined with the growth-inhibitory effects of the antitumor peptide analogues, may make possible improved treatment approaches to adrenal tumors.

[Radiation exposure of patients during 68Ga-DOTATOC PET/CT examinations]. / Strahlenexposition der Patienten bei Untersuchungen mit 68Ga-DOTATOC am PET/CT.

AIM: Investigation of the biodistribution and calculation of dosimetry of Ga-68-DOTATOC- for patients imaged in the routine clinical setting for diagnosis or exclusion of neuroendocrine tumours. PATIENTS, METHODS: Dynamic PET/CT-imaging (Biograph 16) was performed over 20 min in 14 patients (8 men, 6 women) after injection of (112+/-22) MBq 68Ga-DOTATOC followed by whole body 3D-acquisition (8 bed positions, 3 or 4 min each) 30 min p.i. and 120 min p.i.. Urinary tracer elimination was measured and blood activity was derived non-invasively from the blood pool of the heart. The relevant organs for dosimetry were spleen, kidneys, liver, adrenals, urinary bladder and pituitary gland. Dosimetry was performed using OLINDA/EXM 1.0 software and specific organ uptake was expressed as standardized uptake values (SUVs). RESULTS: Rapid physiological uptake of the radiotracer could be demonstrated in liver, spleen and kidneys, adrenals and pituitary gland (mean SUVs were 6, 20, 16, 10, and 4, respectively). Radiotracer elimination was exclusively via urine (16% of injected dose within 2h); no redistribution could be observed. The spleen and the kidneys received the highest radiation exposure (0.24 mSv/MBq, 0.22 mSv/MBq resp.), mean effective dose yielded 0.023 mSv/MBq. CONCLUSION: 68Ga-DOTATOC is used extensively for diagnosis of somatostatin receptor positive tumours because it has several advantages over the 111In-labelled ligand. The derived dosimetric values are lower than first approximations from the biological data of OctreoScan. The use of CT for transmission correction of the PET data delivers radiation exposure up to 1 mSv (low dose).

Successful chemotherapy of hepatic metastases in a case of succinate dehydrogenase subunit B-related paraganglioma.

Compared to other familial pheochromocytoma/paragangliomas (PHEO/PGLs), the succinate dehydrogenase subunit B (SDHB)-related PHEO/PGLs often present with aggressive and rapidly growing metastatic lesions. Currently, there is no proven effective treatment for malignant PHEO/PGLs. Here, we present a 35-year-old white man with primary malignant abdominal extra-adrenal 11 cm paraganglioma underwent surgical successful resection. But 6 months later, he developed extensive bone, liver, and lymph nodes metastasis, which were demonstrated by computed tomography scan and the (18)F-fluorodeoxyglucose positron emission tomography. However, his (123)I-metaiodobenzylguanidine scintigraphy was negative; therefore, the cyclophosphamide, vincristine, and dacarbazine (CVD) combination chemotherapy was initiated. The combination chemotherapy was very effective showing 80% overall reduction in the liver lesions and 75% overall reduction in the retroperitoneal mass and adenopathy, and normalization of plasma catecholamine and metanephrine levels. However, plasma levels of dopamine (DA) and methoxytyramine (MTY) were only partially affected and remained consistently elevated throughout the remaining period of follow-up evaluation. Genetic testing revealed an SDHB gene mutation. Here, we present an SDHB-related PHEO/PGL patient with extensive tumor burden, numerous organ lesions, and rapidly growing tumors, which responded extremely well to CVD therapy. We conclude patients with SDHB-related PHEO/PGLs can be particularly sensitive to CVD chemotherapy and may have an excellent outcome if this therapy is used and continued on periodic basis. The data in this patient also illustrate the importance of measuring plasma levels of DA and MTY to provide a more complete and accurate assessment of the biochemical response to therapy than provided by measurements restricted to other catecholamines and O-methylated metabolites.